Microcontrollers, logic devices and other low voltage circuits often include digital outputs to control external devices. Load drivers are used to interface a low voltage digital output to switch high voltage loads, such as turning lights on or off. Opto-couplers are often used for load switch drivers to optically transfer a switch signal across an isolation barrier. Relays can also be used to drive an isolated load. However, the current needed to energize the relay coil is often more than can be supplied by most digital outputs and a transistor or a relay driver is required to interface the relay coil with the digital output. Moreover, relays include moving parts that can degrade over time, and relays generate electromagnetic interference (EMI). Solid state relays or SSRs do not have any moving components. SSRs often use optical isolation to energize an internal LED to illuminate and switch on a photo-sensitive diode (photo-voltaic or PV diode). The PV diode current turns on a back-to-back thyristor, SCR, TRIAC or MOSFET to switch the isolated load, and the optical coupling isolates the low voltage control circuit from the load. Opto-couplers and solid state relays can be packaged in a four-pin integrated circuit package, with two input pins and two output pins. However, non-optical solutions typically require separate power connections in addition to the input and output pins. In addition, separate power must be supplied to operate these non-optical load switch drivers.